130 THE ENTOMOLOGIST. 



amused myself watching the cicadas on the tree trunks, and 

 securing a few specimens as mementos of the occasion. On the 

 following day I returned to Gravosa en route for England. 



(To be continued.) 



A NOTE ON TWO SPECIES OF BASSID ICHNEU- 

 MONID^ PARASITIC ON A SPECIES OF SYRPHID 

 LARVA. 



By A. E. Cameron, M.A., B.Sc. 



In the course of my investigations into the Insect Fauna of 

 the Soil, at the Experimental Laboratory of the Zoological De- 

 partment of the University of Manchester, on which I am at 

 present engaged, I collected in the beginning of April of last year 

 a number of Syrphid pupae with a view to rearing the imagines. 

 As a general rule, the pupae were found lying on the surface of 

 the ground covered over by decaying cut grass, but several were 

 obtained buried in the surface soil to a depth of two to three 

 inches, the full-grown larvas having evidently entered there to 

 pupate. All the pupae, along with some earth, were transferred 

 to a glass jar, care being taken to keep the conditions fairly 

 moist in order to prevent desiccation. On May 8th a small 

 species of ichneumon was observed flying about within the 

 muslin-covered jar, and an examination showed that one of the 

 pupa-cases was empty, being pierced by a small circular aperture 

 at the broad end. The adult ichneumon, which had evidently 

 emerged from the empty Syrphid pupa-case, was identified by 

 Mr. Claude Morley as Homocidus dimidiatus, Schr. (male). Owing 

 to some inexplicable cause my endeavours to rear the adult 

 Syrphid signally failed on this occasion, but recently I have been 

 more fortunate in attaining this object. 



On October 7th last I was successful in obtaining a large 

 number of the larvae of this same Syrphid. In the middle of 

 January they began to pupate, much earlier, indeed, than would 

 happen under natural conditions in the open, this being accounted 

 for by the quickening influence of the higher temperature of the 

 laboratory where the larvas were kept (62° F.). The first adult 

 of this lot appeared on February 3rd, followed by others later, 

 and on February 5th I had the satisfaction of finding another 

 specimen of II. dimidiatus (female), which had emerged from one 

 of the pupa-cases. 



A specimen of the adult Syrphid was examined by Mr. F. E. 

 Edwards, of the Natural History Museum, South Kensington, 

 and he diagnosed it as Platycheirus albimanus, Fab. (female). 



H. dimidiatus belongs to the subfamily Tryphoninae and the 

 tribe Bassides. Morley, in his ' British Ichneumons,' vol. iv. 



